Shimmer Myr Artifact cards flash rules cast magic

[monto]

If I have a shimmer myr on the battlefield and I cast an artifact card during opponent's turn and in response he destroys my Shimmer Myr, is the artifact spell countered?

[Chodie]

I don't think so, you already cast the spell. It would resolve and then that card would destroy shimmer myr.

[Void Elemental]

The spell you played is already on the stack. Getting rid if the Myr won't have any effect on the spell you played.